Answer:
Na₂CO₃ · 10H₂O
Explanation:
The formula for sodium carbonate hydrate is:
Na₂CO₃ · xH₂O
The unknown "x" is the number of water molecules contained in the hydrate.
To find "x" we have to use the hydrogen percentage in the sample, 7.05 % H.
First we calculate the molecular weight of Na₂CO₃ · xH₂O:
molecular weight of Na₂CO₃ · xH₂O = 23 × 2 + 12 + 16 × 3 + 18x
molecular weight of Na₂CO₃ · xH₂O = 106 + 18x g/mole
Now we devise the fallowing reasoning tanking in account 1 mole of Na₂CO₃ · xH₂O:
if in 106 + 18x grams of Na₂CO₃ · xH₂O we have 2x grams of hydrogen
then in 100 grams of Na₂CO₃ · xH₂O we have 7.05 grams of hydrogen
106 + 18x = (100 × 2x) / 7.05
106 + 18x = 28.4x
106 = 28.4x - 18x
106 = 10.4x
x = 106 / 10.4
x = 10.2 ≈ 10
The formula for the washing soda is Na₂CO₃ · 10H₂O.
Answer:
An atom of Al which has 13 protons and 10 electrons is Al cation (Al⁺³)
Explanation:
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other.
For example,
Al atom has 13 protons and 13 electrons. The number of positive and negative charge is equal thus it will be neutral atom.
While the atom of Al which have 13 proton and 10 electron is not neutral. The positive charge is greater than negative by 3. Which means 3 electrons are lose by Al atom and form cation "Al⁺³".
Thus an atom of Al which has 13 protons and 10 electrons is Al cation (Al⁺³)
Answer:
Newton's first and third law of Motion
Explanation:
The laws applying in the example Newton's first and third laws of Motion.
- The first law states that any object at rest (ie. not moving) will stay at rest until it is forced to move by an external force. In this case, said force were the propulsion gases ignited.
- As the hot gases were pushed out from the engine nozzle, there was another force <em>equal in magnitud but opposite in direction</em> (as the gases went down, that force went upwards), said force is directly responsible for the rocket taking off. That is an example of the third law.
Answer:
The correct answer is - so that other scientists can replicate the experiment and make sure the results are correct or to check accuracy.
Explanation:
The data and procudres are required to be recorded or noted correctly so the experiment and research can be replicate and tested for the accuracy of the experiment by other scientist and researcher.
Mandy also need to note procedure, data, variables and other data correctly for the testing the accuracy and replication of the experiment. The replication is essential to check if every thing is correct and result are error free.
Weight is a measure of force
